"Matthew Connor" <connah at gmail.com> wrote:
>Hi all!
>>Would some please explain to me why Microsoft's DNS Cache Resolver has
>it's own built in TTL defaulting to 86400 (24 hours) instead of paying
>attention to the TTL that the domain's name server reports? This is
>very frustrating to me. We set our TTLs on our domains in BIND to be
>3600 (1 hour) so we can change our records and it get updated quickly.
>However, Windows caches names for a day without regard to that setting.
>>It seems that since Windows being as ubiquitous as it is, the TTL
>setting on an SOA record is meaningless.
>>>I'm not just griping; I am truly hoping that I am wrong and someone
>will set me straight. I would ultimately like to have control over how
>long a client caches my domain's IP but it seems like Windows overrides
>>me. Thanks for any input!
I just ran a test. I typed this command:
dig mx.sth1.isc.org @ns-ext.sth1.isc.org.
and in the response I see
;; AUTHORITY SECTION:
sth1.isc.org. 1H IN NS ns-ext.sth1.isc.org.
sth1.isc.org. 1H IN NS ns-ext.isc.org.
sth1.isc.org. 1H IN NS ns-ext.lga1.isc.org.
sth1.isc.org. 1H IN NS ns-ext.nrt1.isc.org.
Note the 1H TTL. I then went to my Windows 2003 DNS Server and typed:
nslookup
server hippo308.anl.gov
mx.sth1.isc.org
and I received the answer
Name: mx.sth1.isc.org
Address: 192.228.89.21
I then opened the DNS management console and looked at the cached
entries. I see
ns-ext.nrt1.isc.org 192.228.90.19 TTL 0:0:58:28
This shows me that the nslookup query on the W2k+3 box produced a
cached entry with a correct TTL of 1H, which I then queried 1 1/2
minutes later.
What leads you to a different conclusion? What build level of dns.exe
are you running?
----------------------------------------------------------------------
Barry S. Finkel
Computing and Information Systems Division
Argonne National Laboratory Phone: +1 (630) 252-7277
9700 South Cass Avenue Facsimile:+1 (630) 252-4601
Building 222, Room D209 Internet: BSFinkel at anl.gov
Argonne, IL 60439-4828 IBMMAIL: I1004994